I hadn't heard that story before (it's before my time). Thank you for sharing it. I found some articles from the 80s discussing it as one "superstar" with 3500 solar masses and 150 million solar luminosities. That would have been crazy. R136a1 is already pushing limits as it is.

Among those stars is R136a1, which is the single most massive and most luminous star we've found. It is 291 times more massive than the Sun and 7,244,000 times brighter. (3/3)

Image Credit: NASA, ESA, & F. Paresce (INAF-IASF), R. O'Connell (U. Virginia) et al.

🔭⚛️🧪🛰️

The cluster here, known as R136, contains hundreds of thousands of stars all tightly packed together, including some of the most massive and luminous stars we know of. It has only just begun to shed its nebula shell, hence the bubble around it. (2/3)

🔭⚛️🧪🛰️

Not on Mercury. The planet has no atmosphere to hold and disperse heat. That means it gets instantly hot in the sunlight and instantly cold in the shadows. No atmosphere also means no winds. I did read once that you may be able to find places of comfortable temperatures beneath the planet's surface.

A solar day is the time it takes for the Sun to return to the same spot in the sky. A sidereal day is one 360° rotation of the planet. Usually a solar day is slightly longer than a sidereal day, as the planet has to rotate a bit extra to catch up with its orbit around the Sun. Venus is the opposite.

Venus is even more complicated, because it rotates opposite to the direction it orbits. This makes its solar day (117 Earth days) shorter than its sidereal day (243 Earth days), which is usually opposite for other planets, and also closer in length. Its year is in between the two at 225 Earth days.

That's the appeal of a fun fact. They satisfy your mind in just the right way, regardless of their value. They scratch a certain itch, so to speak.

This extra long day helps to create the most extreme temperature differences in the solar system. With the Sun moving so slowly and no atmosphere to hold on to heat, the surface swings from a sweltering 790°F (420°C) the day to a frigid -270°F (-170°C) at night. (3/3)

🔭⚛️🧪🛰️

This occurs because of a cosmic interaction known as spin-orbit resonance. Mercury is so close to the Sun that gravity has slowed its rotation to a specific rhythm: it rotates exactly three times for every two laps it takes around the Sun. (2/3)

🔭⚛️🧪🛰️

While the star that formed these jets is not visible in this image, at the end of one of the jets we see a spiral. That's a distant galaxy that just happens to line up behind the edge of the jet. 🔭⚛️🧪🛰️

Image Credit: NASA, ESA, CSA, STScI, JWST

HH objects are found in areas of high star formation and multiple jets can form from one star, lining up with the star's rotational axis. Unlike many stellar phenomena, they only last for a few tens of thousands of years and can change dynamically over the course of only several years. 🔭⚛️🧪🛰️

But a human can easily do the work of 100 robots, at least for now. That could change in the future. And my understanding is that NASA expects to have the proper technology to protect astronauts from cosmic rays by the 2030s, which is the earliest we'd send a person to Mars anyways.

That's a fair take to have. If you ask me, it's because we haven't done anything novel in manned space flight in a long time. If we can get humans to Mars to explore (which Artemis is the start of), then a whole new world of opportunities appears. That's what really has me excited about Artemis.

If interested, I also wrote two previous articles about the Artemis Program. One on the program and its goals and the other breaking down the launch date of Artemis II.

Artemis Program: www.amidthestarstours.com/post/we-chos...

Artemis II Launch Date: www.amidthestarstours.com/post/t-minus...

🔭🧪🛰️

Yes. On a smaller scale, you'd be able to track more drastic changes, but on the galactic scale, the changes would be much harder to register. Regardless, you'd still need long scale of times to register the changes.

From our human perspective, you can think of them as stable, as they will never change in our lifetimes. But from an astrophysical perspective, it's better to say they're not stable and will continue to change and evolve.

Stable is a very relative term in this context. The gaps are thousands of light-years across, and stellar winds move below light speed, so any change they enact will take an extremely long time on human timescales. They will dynamically change, but only when observed on cosmic timescales.

The complex structure of the first image is caused by a combination of gravity pulling and stellar winds pushing at the dust and gas of the galaxy, sculpting it into filaments and webs. (3/3)

🔭⚛️🧪

Image Credit (Both images): ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST and PHANGS-HST Teams

Compare Webb's image of IC 5332 to that taken by Hubble. Hubble sees the world in the visible and ultraviolet spectrums, which reveals a different picture. The interstellar dust of the Webb infrared image is just barely visible as dark patches where the visible and UV light is blocked. (2/3)

🔭⚛️🧪